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Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Sat, 13 Feb 2010 01:59:02 GMT

I tried to create thumbnails with ViewerX and look at the found http://s-code.com/forum/Topic1830-6-1.aspx which works. I have to scale the bitmap myself however.

In the activex methods I found the method GetScreenBitmapScaled, but this always returns a black bitmap. In the activex methods I found the method GetScreenBitmapScaled, but this always returns a black bitmap. Is it a bug?

Also when I set scaleEnable, scaleDen and scaleNum, I get scaled image in the active viewer window. I support this has the server scaled image, right? However when I ask for the ScreenBitmap, I still get the full resolution bitmap. Why?

The goal is to reduce the network traffic by transferring only server scaled bitmaps from the VNC servers to the client.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Sat, 13 Feb 2010 01:59:02 GMT

[quote]Yes please add the server side scaling feature.[/quote]
Most probably it will be added within next two weeks. As I said to add this feature to the ViewerX will take just about 10+ lines of code.

[quote]Is is possible to ask the server for the number of connected clients?[/quote]
Nope, the RFB protocol used by VNC doesn't support such feature.

[quote]I also think that the image corruption with multiple viewers is a bug[/quote]
Actually I think it's a "by design" flaw. I'm a bit familiar with the UltraVNC server internal and I think there is no simple way to fix this problem. So I expect this issue to stay as it's now for a while.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Sat, 13 Feb 2010 00:47:05 GMT

Yes please add the server side scaling feature.
I have only one connection to the server in 99% of all cases so it should be ok.
Is is possible to ask the server for the number of connected clients? It so I could revert to normal mode, when more than one client wants to connect. If the protocol allows that, please also add this to the viewer control.

I also think that the image corruption with multiple viewers is a bug and should be addressed in the ultravnc forums, so this bug can be fixed. Maybe you do this or provide me with enough technical information that I can do this.

Regards
Carsten

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Thu, 11 Feb 2010 01:11:33 GMT

[quote][b]carsten (2/3/2010)[/b][hr]Is this fixed now?[/quote]

It's not hold for now. Technically it's very easy to implement; probably 10 lines of the source code or so. But server-side scaling implementation in UltraVNC server is a complete joke. It only works with a single client. If more than one client connects to such server, the screen image becomes corrupt on all connected clients.
We might add this as an “experimental” feature in the 3.0.3.0 build. But really, the way this feature is implemented in UltraVNC Server makes it totally unusable for any practical purposes.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Thu, 11 Feb 2010 00:28:12 GMT

What ist the status of server side scaling? Is it already implemented? Which version?

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Wed, 03 Feb 2010 17:34:58 GMT

[quote][b]carsten (2/3/2010)[/b][hr]Is this fixed now?[/quote]

Yes, GetScreenBitmapScaled is implemented in the v3.0.2.1. We also updated the C# sample application, with a sample on how to use this API method.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Wed, 03 Feb 2010 17:14:53 GMT

Is this fixed now?

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Wed, 09 Dec 2009 18:31:45 GMT

I've looked at this it does return 1 bit bitmap indeed. I suspect this is the reason why this method is not listed in the CHM file, because it's not exactly working as it supposed to.

This gonna be fixed within 7-10 days.

When the method is fully implemented and ready for public consumption the caller will have to free the HBITMAP handle returned.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Wed, 09 Dec 2009 14:35:43 GMT

Any news on the 2 points?

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Tue, 17 Nov 2009 15:37:45 GMT

To the other question: What should getBitmapScaled return. Should it return the bitmap handle to the scaled bitmap? How many colors should be there (because I get only 1 bit). Do I have to set the number of colors somewhere?

And: How is the owner of the handle? How has to free it? Is it the caller how has to free this bitmap? I saw that I get another bitmap handle each time I call the functions, os I suppose I have to free it too. In contrast getScreenBitmap seems to always return the same handle, and I must not free it. Right?

This information and also some functions are not documented in the help file. Perhaps you could add the information.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Tue, 17 Nov 2009 06:05:37 GMT

hmm...that's interesting. I'll have to check on this also. If UVNC really supports it, support for the server side scaling feature will be added to the ViewerX and VNC Manager within one or two weeks.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Tue, 17 Nov 2009 01:41:57 GMT

UltraVNC does support Server-Side-Scaling:

1) Please check the main page: http://www.uvnc.com

Citation: "Key features: File transfer, Video driver, Optional Encryption Plugins, MS Logon, Text chat, Viewer Toolbar, Java Viewer with File Transfer , as well as Auto scaling and Server Side Scaling, Multiple-Monitors-support,Repeater/Proxy-support, Auto reconnection, good performances and tons of other functionalities."

2) Please see Screenshot of advanced viewer options dialogbox at http://www.uvnc.com/install/viewerconfig.html

In the lower part of the screen you see "Server screen scale by 1/xxx". Here the nominator is always 1 and you can select a denominator. So I supposed this is exactly your scaleDen property.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Mon, 16 Nov 2009 23:15:58 GMT

[quote]1) So what is the method GetScreenBitmapScaled for? I just returns a block 1 bit bitmap? Isn't this a bug?[/quote]
I'll be able to answer to this question when I return back to Singapore from Microsoft PDC conference in LA later this week.

[quote]ULTAVNC does support server side scaling[/quote].
UltraVNC DOESN'T support server side scaling. None of xxxxVNCs support this feature.

[quote]Are the scaleEnable, scaleDen and scaleNum the properties which set server side scaling? In an ULTRAVNC client, they are quite similar (apart from scale numerator beeing always[/quote]
Yep they have the same meaning as in UltraVNC. But they using these properties you will get a scaled window. So if you would want to resize the viewer window you would have to come up with appropriate ScaleNum/Den value.
That's why it's better to use EnableScalling property and setup the stretching mode: Free or Aspect scaling.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

carsten — Mon, 16 Nov 2009 15:22:24 GMT

1) So what is the method GetScreenBitmapScaled for? I just returns a block 1 bit bitmap? Isn't this a bug?

2) ULTAVNC does support server side scaling. Are the scaleEnable, scaleDen and scaleNum the properties which set server side scaling? In an ULTRAVNC client, they are quite similar (apart from scale numerator beeing always 1). What are the scale* properties for? Is it also client scaling? But this could also be done with strech mode.

RE: Thumbnails GetScreenBitmapScaled, scaleEnable

Support (s-code) — Sun, 15 Nov 2009 20:46:32 GMT

[quote]image, right? However when I ask for the ScreenBitmap, I still get the full resolution bitmap. Why?[/quote]
ScreenBitmap returns bitmap without scalling by design.

[quote]The goal is to reduce the network traffic by transferring only server scaled bitmaps from the VNC servers to the client[/quote]
I wish it was possible...Unfortunatelly VNC server doesn't support server-side scalling and there is nothing we can do about it.